#include <iostream>
#include <iomanip>
using namespace std;
int main()
{
    float num1, num2, num3;
    cout << "please input three numbers:";
    cin >> num1 >> num2 >> num3;
    cout << setw(8) << setprecision(12);
    cout << "The average of " << num1 << ", " << num2 << " and " << num3;
    cout << " is: " << setw(20) << (num1 + num2 + num3) / 3 << endl;
    cout << "学号：3170608043，姓名：石英钰" << endl;
    return 0;
}